GSC instrumentation — URL Inspection (live + API, 2,000/day/property cap) is ground truth for a specific URL; Page Indexing report distinguishes Discovered-not-indexed vs Crawled-not-indexed; Performance report normally lags 2–6h

Claim: The Google Search Console instruments practitioners actually use:

• URL Inspection tool / API: ground truth for whether a specific URL is indexed. API allows up to 2,000 queries / day / property. "Request Indexing" is a hint, not a command; duplicate requests are ignored within a crawl cycle (see Rule (R4): do NOT spam-request indexing — duplicate Request-Indexing submissions are ignored within a crawl cycle; "a hint, not a command" (Google)).
• Page Indexing (Coverage) report: distinguishes "Discovered — currently not indexed" (queue/crawl-priority issue — see Search Console "Discovered – currently not indexed" can persist indefinitely — Mueller: "That can be forever. It's something where we just don't crawl and index all pages") from "Crawled — currently not indexed" (page-level quality/relevance issue — see Search Console "Crawled – currently not indexed" is a deliberate quality decision, not a queue state — Google fetched and evaluated the page and CHOSE not to index it). These are different triggers and need different fixes — see Rule (R3): "Discovered – not indexed" and "Crawled – not indexed" have DIFFERENT triggers — first is crawl-priority/site-wide quality signal, second is per-page quality decision; treat them differently.
• Performance report lag: normally 2–6 hours, but is not real-time and not a timing instrument for indexing.
• Crawl Stats report (Settings → Crawl stats): host status + response code/file type breakdowns — see Search Console Crawl Stats report (Settings → Crawl stats) is the primary observability surface for the crawl stage — total requests, average response time, host status, response-code/file-type breakdowns.

Indexing Insight has argued that GSC misreports indexing states for pages being actively forgotten — i.e., the report can show a page as indexed when it has effectively been dropped from active serving. Treat GSC as the best available instrument, not as ground truth.

Source: Google Search Console documentation; Indexing Insight commentary.

Confidence: High on the instrument descriptions; Single-source on the "GSC misreports forgotten pages" claim.

Caveat: "2,000 queries/day/property" is the URL Inspection API limit; Search Console UI usage isn't rate-capped that way. The "Request Indexing" hint-not-command framing is Google's own language.